The manufacture of organic solvents in commercial quantities often results in the production of crude solvents containing at least some level, and often relatively high levels, of impurities. Although such crude solvents are frequently acceptable for certain applications, applicants have recognized that the impurity level in many commercially available sources of organic solvents, particularly methanol, creates significant problems in other applications.
Accordingly, applicants have heretofore attempted to use distillation techniques to remove impurities from a wide variety of commercially available crude methanols to produce methanol having suitably low impurity levels. Unfortunately, applicants have discovered that distillation is not a particularly effective method for removing impurities for a number of reasons. One reason, for example, is that many impurities found in commercial methanols have boiling points that are similar to the boiling point of methanol, thus making them particularly difficult to remove via distillation.
In addition, applicants have discovered that the vast majority of commercially available crude methanols contain levels of impurities so high that it is extremely difficult, if not impossible, to sufficiently lower the amount of impurities via conventional distillation to acceptable levels. Sources of the impurities found in commercially available crude methanol likely include inefficiency at the production site and/or contamination during product handling (for example, cross-contamination from transfer lines, barges, trucks, rail cars, intermediate storage tanks, etc). Accordingly, crude methanols more suitable for distillation could be produced commercially by increasing efficiency at the production site and in product handling. However, such changes would be extremely costly and difficult to control.
Therefore, applicants have developed the present process which allows for the production of high purity solvents from crude solvents.